Sherk does have good standup. He throws a very sharp jab/cross combo but it's to setup a shoot or it's reactionary to his opponent's punching. To KO someone, you have to commit to that objective, he doesn't have the leg drive of someone who means to take you out that way. Defensively, he's unusual for a wrestler in that he keeps his hands at temple height and shells(protects) himself from behind them.
If Sherk would deadleg whip his shin off the floor, he would be breaking ribs out there and a straight left to his opponent's liver, bam, but that's not his trained way and God forbid anyone in MMA would ever attempt double punching in tight. I guess someone like Cung Le would/has.
I should clarify something here. The offensive techniques above, and others like them, are higher reward and risk. For someone, who should use as an example? Arlovski, maybe, it's too high risk because he apparently lacks the great defensive reactionary groundskill and hard chin to a counterstrike that Sherk does. Sherk is so fast, strong, good on the ground and iron jawed that , IMO, he can afford to take these risks and his chances of successful recovery are high.
Sherk just needs to open his game up, he has the tools, he needs some topflight Muay Thai instruction, I think.